SUMMARY
Audit fees are related to important ethical issues for auditors. There has been increasing research on audit fees recently, including research on potential ethical risks regarding audit fees, which helps to illuminate some of these professional issues. The International Ethics Standards Board for Accountants (IESBA) is very interested in this area and asked me to prepare a paper reviewing the relevant research. This summary reviews research that became available from 2006 to 2016 on four issues related to audit fees—fee level, dependence, non-audit fees, and firms that have a significant non-audit services business. Examining the research shows consistent evidence about two issues, namely that audit fees for new engagements are lower and that non-audit services affect independence in appearance. There are two further issues about which there is some concern. First, there are occasional studies reporting evidence that non-audit services provided by an auditor are associated with a loss of independence indicated by lower audit quality, even though most research does not support this conclusion. Second, there has been recent concern about growth in non-audit services to non-audit clients and there is some preliminary evidence that audit quality is lower in firms that have more extensive non-audit businesses. In general, although audit fee research does not convey a message that there are widespread ethical problems, the body of research shows that there are some risk areas.